DC Entertainment has declared today Batman Day, in honor of the Dark Knight’s 75 Anniversary. To celebrate everyone’s favorite brooding-baddie-battling-billionaire, DC has partnered up with participating comic book retailers, bookstores, and libraries all over America to distribute an assortment of Batman-themed collectibles, including free comic books, masks, bookmarks, and more.

Fans who visit any participating retail store can get a free copy of an all-new special edition Detective Comics #27, which includes an updated reimaging of the World’s Greatest Detective’s original 1939 comic book debut, with a script written by bestselling author Brad Meltzer.

Batman Day celebrators who visit participating stores can also find a Batman 75th anniversary cape, bookmarks inspired by classic Batman comic books, and four masks based on different interpretations of Batman’s signature cowl (pictured above), including: the original 1939 look, the groovy 1966 Adam West version (complete with Bat-eyebrows), the grizzled Dark Knight Returns mask, and the more recent New 52 interpretation.

The special edition of Detective Comics #27 which is being given away at participating retail stores is also available here for free download onto any digital platform, in case you don’t want to leave your bat cave. On July 26, DC Entertainment and Random House will be extending Batman Day to bring it to public libraries across the US, as well.